Ocean warming drives rapid dynamic activation of marine-terminating glacier on the west Antarctic Peninsula

• Published in: Nature communications 2023-11, Vol.14 (1), p.7535-7535, Article 7535
• Main Authors: Wallis, Benjamin J., Hogg, Anna E., Meredith, Michael P., Close, Romilly, Hardy, Dominic, McMillan, Malcolm, Wuite, Jan, Nagler, Thomas, Moffat, Carlos
• Format: Article
• Language: English
• Subjects: 704/106/125; 704/106/829/2737; 704/829/2737; Bathymetry; Climate variability; Discharge; Glaciers; Humanities and Social Sciences; Ice; Ice sheets; Ice shelves; Land ice; Measuring instruments; Meltwater; multidisciplinary; Ocean temperature; Ocean warming; Ponding; Satellite observation; Science; Science (multidisciplinary); Seawater; Thinning; Upper ocean; Warm water
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-42970-4

Ice dynamic change is the primary cause of mass loss from the Antarctic Ice Sheet, thus it is important to understand the processes driving ice-ocean interactions and the timescale on which major change can occur. Here we use satellite observations to measure a rapid increase in speed and collapse of the ice shelf fronting Cadman Glacier in the absence of surface meltwater ponding. Between November 2018 and December 2019 ice speed increased by 94 ± 4% (1.47 ± 0.6 km/yr), ice discharge increased by 0.52 ± 0.21 Gt/yr, and the calving front retreated by 8 km with dynamic thinning on grounded ice of 20.1 ± 2.6 m/yr. This change was concurrent with a positive temperature anomaly in the upper ocean, where a 400 m deep channel allowed warm water to reach Cadman Glacier driving the dynamic activation, while neighbouring Funk and Lever Glaciers were protected by bathymetric sills across their fjords. Our results show that forcing by warm ocean water can cause the rapid onset of dynamic imbalance and increased ice discharge from glaciers on the Antarctic Peninsula, highlighting the region’s sensitivity to future climate variability. Warm ocean waters and favourable bathymetry caused Cadman Glacier on the Antarctic Peninsula to increase speed by 94% from 2018 to 2019. This led to increased ice discharge, glacier retreat of 8 kilometres, and glacier thinning by 20 meters per year.